This Fish Trapped Inside a Jellyfish Is Probably Having a Worse Day Than You

"I've made a terrible mistake."

FIONA MACDONALD

8 JUN 2016

Sometimes life can make you feel like you're going nowhere fast, but spare a thought for this poor fish trapped inside a jellyfish, photographed off the coast of Australia's Byron Bay at the end of last year.

Local photographer Tim Samuel stumbled across this incredibly rare phenomenon while free diving with videographer Franny Plumridge, and the image went viral this week when he posted it on Reddit. The craziest part? The fish was actually able to propel the jellyfish forward and control its direction from its see-thru prison.

"The fish was trapped in there, but controlled the jellyfish's movement," Samuel wrote on Reddit. But he said the fish would have a difficult time swimming in a straight line. "The jellyfish would knock him off course though, and every now and then it would get stuck swimming in circles."

It's one of the first times this behaviour has been caught on camera in this region, as far as experts know.

"I knew I had stumbled upon something pretty special, but I didn't realise no one had photographed this behaviour before, and I haven't heard of anyone ever seeing this before," Samuel told Mashable Australia.

So what's going on here? It's hard to identify the species of fish or jellyfish from these photos alone, but Ian Tibbetts, a fish biologist from the Centre of Marine Science at the University of Queensland, told Australian Geographic that the jellyfish appears to be a type of stinging jellyfish known as a cubomedusan.

And the fish appears to be a juvenile trevally, which means - despite appearances - it might have actually got up-close-and-personal with the jellyfish intentionally, rather than becoming trapped by accident.

That's because young trevally are known to seek shelter among the stingers of certain jellyfish species, to help protect them from predators. Although they usually don't end up right up inside them.

"It's difficult to tell whether disaster has just struck, or whether the fish is happy to be in there," Tibbetts told Australian Geographic. "Although by the photographer's description of the fish swimming, my guess is that it is probably quite happy to be protected in there."

The good news is that the fish is probably way too big for the jellyfish to actually eat with any ease - with most preferring to move smaller organisms such as plankton, brine shrimp, or fish eggs into their stomach.

The bad news is that means the fish might have also interrupted the jellyfish's feeding. Or maybe it's a yet-to-be-discovered symbiotic behaviour that benefits both of them somehow - researchers will have to investigate further.

So what was the fate of this poor unfortunate duo? We'll never know, but Samuel insists that despite his initial instincts, he decided to leave the pair alone.

"I contemplated freeing the fish as I felt bad for it, but in the end decided to just let nature run its course, which was a difficult decision for me to make," Samuel told Gizmodo. "I don’t know what happened to them."